SIST ETS 300 326-3 E1:2003

• Abstract:

  Standardisation of a public telecommunication system for aircraft to provide voice services, using a cellular direct air-ground radio transmission system.

• Status: Published
• Publication Date: 30-Nov-2003
• ICS: 33.060.01 - Radiocommunications in general
• ICS: 49.090 - On-board equipment and instruments
• Technical Committee: SS EIT - Technical Board for the electrotechnical, information technology and telecommunications fields
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Dec-2003
• Due Date: 01-Dec-2003
• Completion Date: 01-Dec-2003
• Ref Project: ETSI ETS 300 326-3 ed.1 (1996-02) - Radio Equipment and Systems (RES); Terrestrial Flight Telecommunications System (TFTS); Part 3: Speech services, network aspects

SIST ETS 300 326-3 E1:2003 is the Slovenian adoption of ETS 300 326-3 Edition 1 from ETSI. It specifies the speech services and network aspects of the Terrestrial Flight Telecommunications System (TFTS), a public telecommunication system for aircraft using cellular direct air-ground radio transmission. The standard is for designers, integrators, and operators who need interoperable TFTS ground and airborne equipment, including call handling, interworking, and handover behavior.

What does SIST ETS 300 326-3 E1:2003 specify?

SIST ETS 300 326-3 E1:2003 specifies the network-side behavior needed to provide Aeronautical Public Correspondence (APC) voice service through TFTS. It focuses on the functions and procedures that keep TFTS equipment interoperable across aircraft, ground stations, switching centres, and fixed networks.

The scope places TFTS in the WARC 92 spectrum bands and says that the standard fully specifies the radio-interface and ground-network aspects needed to maintain interoperability. It also states that the work expands the general architecture in ETS 300 326-1 and uses ETS 300 326-2 for the signalling-linked parts of handover and call handling.

A key point is that the standard covers fixed-network interworking by function, not by choosing a single signalling system. In practice, that means implementers have to meet the required behavior at the interfaces without being forced into one proprietary network protocol.

The contents are organized around:

• clause 1, scope
• clause 2, normative references
• clause 3, definitions and abbreviations
• clause 4, TFTS network architecture
• clause 5, fixed network interworking
• clause 6, call handling and handover procedures

What are the key requirements of SIST ETS 300 326-3 E1:2003?

SIST ETS 300 326-3 E1:2003 turns the TFTS service into a set of implementable network rules. The most important requirements are about architecture, interworking, call handling, and handover control.

Network architecture and reference points

Clause 4 defines the TFTS functional entities: the Ground Station System (GSS), Ground Switching Centre (GSC), Ground Station (GS), Interworking Function (IWF), and Aircraft Station (AS). It also defines the main interfaces, including the interface between GSC and GSs (Ub) and the interface between AS and GS system (Ua).

In practice, this tells equipment makers where each function belongs and where information must cross between subsystems. It matters because interoperability depends on both sides of an interface interpreting the same roles and data exchange points.

Clause 4 also describes the TFTS network configuration and the interfaces with fixed networks. The standard explicitly says that it does not define a specific signalling system for fixed-network interworking, only the required functionality.

Connection types and bearer description

Clause 4.7 introduces TFTS network connection types. The standard uses them as a controlled description of TFTS connections that have the same characteristics.

This matters because TFTS terminals and ground systems need a common way to describe the service they are setting up, rather than relying on local interpretation. Clause 4.7 also explains the relationship between bearer and connection types and lists the attributes used to define them.

Fixed-network interworking

Clause 5 sets the requirements for interworking with fixed networks. It distinguishes between network interworking and service interworking, and it describes the traffic part used for that interworking.

The clause covers interworking to the PSTN/ISDN and to the ISDN. For speech calls in ISDN, the teleservice "Telephony" is used. For operators, the practical effect is that TFTS must present speech calls in a way that fixed networks can accept and route without ambiguity.

Call handling and handover strategy

Clause 6.2 defines handover criteria and resource allocation management. It covers when the AS needs handover, when the GS needs handover, how handover decisions are prioritized, and how resource shortages are handled.

Clause 6.3 then sets out the call handling and handover management procedures. These procedures are linked to the signalling of ETS 300 326-2, so the call control behavior and the radio-signalling behavior work together.

In practice, this is the part that determines whether a call can stay up when aircraft move between cells. Designers need to implement both the decision logic and the failure actions, because the standard also covers what to do when a handover cannot be completed.

Handover signalling functions and messages

Clause 6.5 is the detailed handover signalling specification. It splits the work among Handover Resource Management (HRM), Call Control Management (CCM), Maintenance Resource Management (MRM), the RF, and the Distribution Function (DF).

This clause matters because it tells systems how to exchange handover requests, confirmations, rejects, release messages, and maintenance data. It also gives the message formats, information-element coding, and error handling rules, so different implementations can exchange the same handover information consistently.

GSC isolation and restoration

Clause 6.6 covers GSC-GSC isolation and restoration. It includes restart behavior, handover resource states, handover resource maintenance, and the related service and acknowledge messages.

For operations staff, this is the part that supports recovery after a switching centre isolation or restart. For designers, it defines how handover resource state must be tracked so the network can recover in a controlled way.

What terms does SIST ETS 300 326-3 E1:2003 define?

• Digital connection - A combination of transmission channels, circuits, switching, and other functions used to transfer digital signals between points for one communication.
• TFTS connection - A connection established through TFTS between specified TFTS reference points.
• TFTS connection type - A description of a group of TFTS connections that share the same characteristics.
• Ground Station System (GSS) - The collection of TFTS ground-station functions that supports the service at the ground side.
• Ground Switching Centre (GSC) - The switching centre that controls TFTS connections and handover-related signalling in the ground network.
• Ground Station (GS) - The ground station that provides the radio link toward the aircraft.
• Aircraft Station (AS) - The airborne station on the aircraft side of TFTS.
• Handover Resource Management (HRM) - The function that manages handover resources and the signalling used to control them.

Who uses SIST ETS 300 326-3 E1:2003?

SIST ETS 300 326-3 E1:2003 is used by aircraft communications suppliers, ground station and switching-centre vendors, and aeronautical network operators. It is also relevant to systems integrators who connect TFTS with fixed networks and to test laboratories that verify interoperability.

In practice, these users apply it when they design call handling, implement inter-GSC handover, code signalling messages, or check how TFTS speech calls interact with PSTN, ISDN, and PSPDN environments. Airline avionics and communications teams may also use it when they assess aircraft-side compatibility with the TFTS architecture.

Which standards are used with SIST ETS 300 326-3 E1:2003?

Normative reference	What it contributes
ETS 300 326-1	The general TFTS architecture, speech services, facilities, and requirements.
ETS 300 326-2	The radio aspects and signalling framework used by the call-handling and handover procedures.
CCITT E.164 and E.163	Numbering plans for ISDN-era and international telephone services.
CCITT I.112 and I.310	ISDN vocabulary and functional principles.
CCITT X.25, X.1, X.121, X.200, X.210	Packet-mode and OSI concepts used in the interworking description.
ERC/DEC (92)01	The frequency bands allocated for the Pan European TFTS.
ARINC Characteristic 752	The airborne TFTS subsystem reference used for aircraft-side alignment.

What does the SIST ETS 300 326-3 E1:2003 document contain?

SIST ETS 300 326-3 E1:2003 contains network architecture descriptions, fixed-network interworking rules, and detailed call-handling and handover procedures. It also includes message definitions, information-element coding, and error-handling behavior for handover resource signalling.

The document uses tables to define connection attributes and message elements, and it uses figures and state diagrams to show HRM behavior and GSC-GSC isolation/restoration. Those parts are the implementation material for design, verification, and interoperability testing.

Clause 6 is the most detailed part. It gives the procedural flow for handover, the functional split between HRM, CCM, MRM, RF, and DF, and the octet-level structure of the signalling messages.

For implementers, the document is most useful as a reference for making TFTS call control and handover behavior consistent across different vendors and network domains.

SLOVENSKI STANDARD
01-december-2003
Radijska oprema in sistemi (RES) – Prizemni letalski telefonski sistem (TFTS) – 3.
del: Govorne storitve, omrežni vidiki
Radio Equipment and Systems (RES); Terrestrial Flight Telecommunications System
(TFTS); Part 3: Speech services, network aspects
Ta slovenski standard je istoveten z: ETS 300 326-3 Edition 1
ICS:
33.060.01 Radijske komunikacije na Radiocommunications in
splošno general
49.090 2SUHPDLQLQVWUXPHQWLY On-board equipment and
]UDþQLKLQYHVROMVNLKSORYLOLK instruments
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN ETS 300 326-3
TELECOMMUNICATION January 1996
STANDARD
Source: ETSI TC-RES Reference: DE/RES-5-01/13
ICS: 33.060.50
TFTS, network aspects
Key words:
Radio Equipment and Systems (RES);
Terrestrial Flight Telephone System (TFTS);
Part 3: Speech services, network aspects
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
F-06921 Sophia Antipolis CEDEX - FRANCE
Postal address:
650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
Office address:
c=fr, a=atlas, p=etsi, s=secretariat - [e-mail]
X.400: Internet:
Tel.: [phone] - Fax: [phone]
Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and the
foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 1996. All rights reserved.
New presentation - see History box

Page 2
ETS 300 326-3: January 1996
Whilst every care has been taken in the preparation and publication of this document, errors in content,
typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to
"ETSI Editing and Committee Support Dept." at the address shown on the title page.

Page 3
ETS 300 326-3: January 1996
Contents
Foreword .9
1 Scope .11
2 Normative references.11
3 Definitions and abbreviations .12
3.1 Definitions .12
3.2 Abbreviations .12
4 TFTS network architecture.13
4.1 General .13
4.2 The functional entities of the TFTS.13
4.2.1 The Ground Station System (GSS).13
4.2.2 The GSC .14
4.2.3 The GS.14
4.2.4 The Interworking Function (IWF) .14
4.2.5 The AS .14
4.3 Configuration of the TFTS network.14
4.3.1 General.14
4.3.2 Description of the TFTS configuration.15
4.4 TFTS network interfaces.16
4.4.1 General.16
4.4.2 Interface between the GSC and GSs (Ub).16
4.4.3 Interface between AS and GS system (Ua) .16
4.5 Interfaces with the fixed networks.16
4.5.1 Interface between the GSC and the fixed networks.16
4.5.2 Scope of TFTS specification .16
4.6 Interfaces between AC, OMC and NMC, and the fixed networks.17
4.7 Network connection types.17
4.7.1 Introduction.17
4.7.2 General considerations .17
4.7.2.1 Relationship between lower layer capabilities and radio
traffic channels .17
4.7.2.2 Lower layer capabilities.17
4.7.3 Framework for the description of connection types.17
4.7.3.1 Introduction.17
4.7.3.2 Purpose of TFTS connection types .18
4.7.3.3 Functions associated with TFTS connection.18
4.7.3.4 Applications of TFTS connection types .19
4.7.4 TFTS connection types .19
4.7.4.1 Description of TFTS connection types.19
4.7.4.2 TFTS connection elements.20
4.7.4.3 Rules of association for the attribute values of connection
elements and connection types .20
4.7.4.3.1 Information transfer mode .20
4.7.4.3.2 Information transfer rate (kbits/s).20
4.7.4.3.3 Information transfer susceptance .20
4.7.4.3.4 Establishment of connection.20
4.7.4.3.5 Symmetry.21
4.7.4.3.6 Connection configuration .21
4.7.4.3.7 Structure .21
4.7.4.3.8 Channels.21
4.7.4.3.8.1 Information channel (rate).21
4.7.4.3.8.2 Signalling channel (rate) .21
4.7.4.3.9 Connection control protocol .21
4.7.4.3.10 Information transfer coding/protocol .21

Page 4
ETS 300 326-3: January 1996
4.7.4.3.11 Further attributes and attribute values . 22
4.7.4.4 Limited set of TFTS connection types. 22
4.7.5 Relationship between bearer and connection types . 23
4.7.6 List of definitions of TFTS connection type attributes and their values . 24
4.7.6.1 Attribute definition and their values. 24
4.7.6.2 Definition of values. 25
5 Fixed network interworking. 25
5.1 Interworking requirements. 25
5.1.1 Interworking definition. 25
5.1.2 Interworking between networks . 25
5.1.2.1 Network interworking . 25
5.1.2.2 Service interworking. 26
5.2 Network interworking traffic part. 26
5.2.1 General . 26
5.2.2 Definitions . 26
5.2.3 Traffic part introduction. 27
5.2.4 Network characteristics . 27
5.2.4.1 Key characteristics of networks concerned. 27
5.2.4.2 Characteristics of PSTNs. 27
5.2.4.3 Interworking classification . 28
5.2.4.3.1 Network interworking. 28
5.2.4.3.2 Signalling interworking . 28
5.2.4.3.3 Numbering. 28
5.2.5 Interworking to the PSTN/ISDN. 29
5.2.5.1 Interworking indications to TFTS terminals. 29
5.2.5.2 Transmission aspects . 29
5.3 Interworking to the ISDN . 29
6 Call handling and handover procedures. 30
6.1 General. 30
6.2 Handover criteria and resource allocation management. 30
6.2.1 General . 30
6.2.2 General handover decisions. 30
6.2.2.1 AS need for handover . 30
6.2.2.2 GS need for handover. 30
6.2.2.3 Handover decision point priority. 31
6.2.3 Handover strategy to be applied at AS . 31
6.2.4 Handover strategy to be applied at AS for cell boundary selection . 31
6.2.5 Alternative handover strategy to be applied at AS for cell boundary
selection. 31
6.2.6 Conflict in signalling requirements. 31
6.2.7 Resource management strategy to be applied at the GS. 32
6.2.7.1 General requirements on GS resource management. 32
6.2.8 Handover failure actions due to lack of resources. 33
6.2.8.1 Handover failure action at the GS side due to lack of
resources . 33
6.2.8.2 AS action on handover failure due to resource shortage. 33
6.2.8.2.1 Handover initiated due to poor link quality . 33
6.2.8.2.2 Handover initiated due to cell boundary. 33
6.2.8.2.3 Handover initiated due to physical condition. 33
6.2.9 General handover and cell selection issues . 34
6.3 Call handling and handover management procedures . 34
6.3.1 General . 34
6.3.2 Call handling procedures . 34
6.3.2.1 General aspects. 34
6.3.2.2 Functional aspects for call handling. 35
6.3.2.2.1 AS functional entities. 35
6.3.2.2.2 GS functional entities . 36
6.3.2.2.3 GSC functional entities. 36
6.3.2.3 Call handling phases. 36
6.3.2.3.1 Resource set-up phase. 37
6.3.2.3.2 Call set-up phase . 38

Page 5
ETS 300 326-3: January 1996
6.3.2.3.3 Conversation phase.38
6.3.2.3.4 Call release phase .38
6.3.2.3.5 Resource Release phase .39
6.3.3 Handover procedures.39
6.3.3.1 Handover decision.39
6.3.3.1.1 Reasons for handover .39
6.3.3.1.1.1 Reason for handover initiation on the
AS side.39
6.3.3.1.1.2 Reason for handover initiation on the
GS side .39
6.3.3.1.2 Strategy for Handover.40
6.3.3.2 Handover management.40
6.3.3.2.1 Resource management .40
6.3.3.2.2 Handover phase organisation.40
6.3.3.2.2.1 Negotiation phase.40
6.3.3.2.2.2 Execution phase .40
6.3.3.2.2.3 Completion phase.41
6.3.3.2.3 Failure procedures.41
6.3.3.3 Functional composition of TFTS stations .41
6.3.3.3.1 AS functional composition for
handover.42
6.3.3.3.2 GS functional composition for
handover.43
6.3.3.3.2.1 Functional composition for handover
between carriers of a GS .43
6.3.3.3.2.2 Functional composition for a previous
GS in handover between different
GSs.44
6.3.3.3.2.3 Functional composition for a new GS
in handover between different GSs. .45
6.3.3.3.3 GSC functional composition for
handover.45
6.3.3.3.3.1 GSC Signalling functions for handover between GSs of
the same GSC .47
6.3.3.3.3.2 Signalling functions for a GSC requesting handover.48
6.3.3.3.3.3 Signalling functions for a handover requested GSC.49
6.3.3.4 Handover general description.50
6.3.3.4.1 Handover between channels of the GS.50
6.3.3.4.1.1 General description of handover between channels of the
GS.50
6.3.3.4.1.2 Description of handover between channels of the GS .51
6.3.3.4.1.3 Handover between GSs of the same GSC.52
6.3.3.4.1.4 Description of handover between GSs of the same GSC .53
6.3.3.4.2 Handover between GSs of different GSC.55
6.3.3.4.2.1 General description of handover
between GSs of different GSC .55
6.3.3.4.2.2 Description for handover between
GSs of different GSC.56
6.4 Network interworking handover part .58
6.4.1 General.58
6.4.2 TFTS/PSPDN interworking requirements .58
6.4.3 TFTS/ISDN interworking requirements .59
6.4.4 TFTS/PSTN interworking requirements .59
6.5 Handover part specification .59
6.5.1 Introduction.59
6.5.2 Interface presentation.59
6.5.2.1 General.59
6.5.2.2 Objectives.60
6.5.2.3 General characteristics.61
6.5.2.3.1 Technique of description.61
6.5.2.3.2 Primitives .61
6.5.2.3.3 Peer-to-peer communication .61
6.5.3 Structure of signalling functions .61

Page 6
ETS 300 326-3: January 1996
6.5.3.1 Basic groups of functions. 61
6.5.3.2 Protocol architecture . 61
6.5.4 Services provided by handover signalling layer. 63
6.5.4.1 CC services. 63
6.5.4.2 MRM services . 63
6.5.4.3 HRM services. 63
6.5.5 Services assumed from network layer. 63
6.5.5.1 General . 63
6.5.5.2 Service primitives. 64
6.5.6 Inter-layer service interfaces. 64
6.5.6.1 Services provided by HRM entity . 64
6.5.6.1.1 General. 64
6.5.6.1.2 Service primitives . 65
6.5.7 Functions to be provided by the handover layer entities. 66
6.5.7.1 Functions provided by the HRM entity . 66
6.5.7.2 Functions provided by the CCM entity . 67
6.5.7.3 Function provided by the RF . 67
6.5.7.4 Functions provided by the Distribution Function (DF). 67
6.5.7.5 Functions provided by the MRM entity. 67
6.5.8 Elementary procedures for HRM . 67
6.5.8.1 General . 67
6.5.8.2 Transport CM . 67
6.5.8.3 HRM. 68
6.5.8.4 Handover processing . 68
6.5.8.4.1 Outgoing handover procedure . 68
6.5.8.4.2 Incoming handover procedure . 69
6.5.8.5 Handover information transmission . 69
6.5.8.6 TCH release. 69
6.5.8.7 Data message transmission . 70
6.5.9 Message functional definition and contents. 70
6.5.9.1 Messages for HRM . 71
6.5.9.2 Handover resource messages. 71
6.5.9.2.1 TCH release. 71
6.5.9.2.2 Release Confirm . 72
6.5.9.3 Handover messages between GSCs. 72
6.5.9.3.1 HO-Request . 72
6.5.9.3.2 HO-Confirm. 72
6.5.9.3.3 HO-Command. 73
6.5.9.3.4 HO-Complete . 73
6.5.9.3.5 HO-Reject . 74
6.5.9.3.6 HO-Failure. 74
6.5.9.3.7 HO-Information. 74
6.5.9.4 Miscellaneous messages. 75
6.5.9.4.1 Connect. 75
6.5.9.4.2 Disconnect . 75
6.5.9.4.3 CCM message transfer . 75
6.5.9.4.4 MRM message transfer. 76
6.5.9.5 Messages for MRM. 76
6.5.10 Message format and information element coding . 76
6.5.10.1 Overview . 76
6.5.10.2 Message type. 77
6.5.10.3 Other information elements. 77
6.5.10.3.1 HRM information elements. 81
6.5.10.3.2 Handover procedure reference . 81
6.5.10.3.3 GS Identifier . 82
6.5.10.3.4 ATEI . 82
6.5.10.3.5 Handover resource identifier . 83
6.5.10.3.6 Handover resource description . 83
6.5.10.3.7 Handover call number . 84
6.5.10.3.8 Handover resource identifier list. 85
6.5.10.3.9 Handover characteristics. 86
6.5.10.3.10 Allocated frequency. 86
6.5.10.3.11 Allocated slots . 87

Page 7
ETS 300 326-3: January 1996
6.5.10.3.12 HRM Cause .87
6.5.10.3.13 CCM data message.88
6.5.10.3.14 MRM data message.89
6.5.11 Handling of error conditions .89
6.5.11.1 Transport disconnect.89
6.5.11.2 Release resource already released.89
6.5.11.3 Unknown handover resource identifier .89
6.5.11.4 Unknown handover reference .89
6.5.12 Handover diagrams.90
6.5.12.1 Handover scenario diagrams.90
6.5.12.1.1 Normal case.90
6.5.12.1.2 Reject by Old-GSC .90
6.5.12.1.3 Reject by New-GSC.91
6.5.12.1.4 Reject by the New-GS .91
6.5.12.1.5 Reject by the New-GSC after HO-
CONFIRM .91
6.5.12.1.6 Failure by the AS .92
6.5.12.2 State diagram and System Description Language (SDL)
of HRM.93
6.6 GSC - GSC isolation and restoration.102
6.6.1 General.102
6.6.2 Isolation .102
6.6.3 Handover resource states .102
6.6.3.1 Handover resource dynamic states .102
6.6.3.2 Handover resource usage states.102
6.6.4 Restart procedure.103
6.6.4.1 General restart procedure .103
6.6.4.2 Handover resource dynamic state diagram.104
6.6.5 Handover Resource Maintenance.104
6.6.5.1 Handover resource usage state modification procedure.104
6.6.5.2 Handover resource usage state diagram .105
6.6.6 Messages functional definition and contents.105
6.6.6.1 Restart message .105
6.6.6.2 Restart acknowledge message .106
6.6.6.3 Service message .106
6.6.6.4 Service acknowledge message.106
6.6.7 Message format and information element coding .106
6.6.7.1 General message format.107
6.6.7.2 Message type .107
6.6.7.3 Other information elements .108
6.6.7.4 MRM transaction reference .108
6.6.7.5 Handover resource identity and state.109
History.110

Page 8
ETS 300 326-3: January 1996
Blank page
Page 9
ETS 300 326-3: January 1996
Foreword
This European Telecommunication Standard (ETS) has been produced by the Radio Equipment and
Systems (RES) Technical Committee of the European Telecommunications Standards Institute (ETSI).
This ETS has been split into three parts as follows:
Part 1: "Speech services, facilities and requirements";
Part 2: "Speech services, radio interface";
Part 3: "Speech services, network aspects".
Proposed transposition dates
Date of adoption of this ETS: 26 May 1995
Date of latest announcement of this ETS (doa): 30 April 1996
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 31 October 1996
Date of withdrawal of any conflicting National Standard (dow): 31 October 1996

Page 10
ETS 300 326-3: January 1996
Blank page
Page 11
ETS 300 326-3: January 1996
1 Scope
This European Telecommunications Standard (ETS) covers the specification of equipment for provision of
a terrestrial Aeronautical Public Correspondence (APC) service working in the frequency spectrum bands
allocated at World Administrative Radio Conference (WARC) 92 (1 670 to 1 675 MHz and 1 800 to 1 805
MHz). The ETS fully specifies aspects of the radio interface and Terrestrial Flight Telecommunication
System (TFTS) Ground Network (GN) required to maintain interoperability of equipment. Within Europe
European Radiocommunications Committee (ERC) Decision ERC/DEC (92)01 [13] is applicable to TFTS
frequency spectrum.
The general architecture of the TFTS is considered in ETS 300 326-1 [1]. This part expands on that
explanation to consider aspects of fixed network interworking. This part does not specify any specific
signalling system for that purpose. It only specifies the functionality required for correct operation of the
system.
Call handling and decision processes are specified. These should be used in conjunction with ETS 300
326-2 [2]. These explanations include the decision processes for the handover function.
Signalling requirement between Ground Switching Centres (GSCs) are specified for supporting inter-GSC
handovers.
The TFTS Aircraft Station (AS) was specified by the European Airlines Electronics Committee (EAEC) and
has subsequently been adopted as Aeronautical Public Correspondence (ARINC) Characteristic 752 [14]
by the Airlines Electrical Engineering Committee (AEEC). ARINC Characteristic 752 [14] makes reference
to this ETS for specification of certain radio and telecommunication matters to avoid ambiguity. The TFTS
AS is one of a set of facilities within an overall architecture being defined for aircraft on board
telecommunications by the AEEC.
An Interim European Telecommunications Standard (I-ETS) is being produced which covers aspects of
conformance testing for TFTS aircraft mobile stations. The specification of data application and facsimile
will be the subject of a further (I-)ETS.
2 Normative references
This ETS incorporates by dated or undated reference, provisions from other publications. These
normative references are cited at the appropriate places in the text and the publications listed hereafter.
For dated references, subsequent amendments to or revisions of any of these publications apply to this
ETS only when incorporated in it by amendment or revision. For undated references the latest edition of
the publication applies.
[1] ETS 300 326-1 (1995): "Radio Equipment and Systems (RES); Terrestrial Flight
Telephone System (TFTS); Part 1: Speech services, facilities and
requirements".
[2] ETS 300 326-2 (1995): "Radio Equipment and Systems (RES); Terrestrial Flight
Telephone System (TFTS); Part 2: Speech services, radio aspects".
[3] CCITT I-Series of Recommendations (I.500 - I.605).
[4] CCITT Recommendation E.164 (1988): "Numbering plan for the ISDN era".
[5] CCITT Recommendation E.163: "Numbering plan for the international telephone
service".
[6] CCITT Recommendation I.112: "Vocabulary of terms for ISDNs".
[7] CCITT Recommendation I.310: "ISDN-Network functional principles".
[8] CCITT Recommendation X.25: "Interface between data terminal equipment
(DTE) and data circuit-terminating equipment (DCE) for terminals operating in
the packet mode and connected to public data networks by dedicated circuit".

Page 12
ETS 300 326-3: January 1996
[9] CCITT Recommendation X.1: "International user classes of service in public
data networks and integrated services digital networks".
[10] CCITT Recommendation X.121: "International numbering plan for public data
networks".
[11] CCITT Recommendation X.200 (1988): "Reference model of open system
interconnection for CCITT applications".
[12] CCITT Recommendation X.210 (1988): "Open systems interconnection layer
service definition".
[13] ERC Decision ERC/DEC (92)01: "Definition of frequency bands for the Pan
European terrestrial flight telephone system (TFTS)".
[14] ARINC Characteristic 752: "Terrestrial Flight Telephone System (TFTS)
Airborne Radio Subsystem".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of this ETS, the following definitions apply:
(digital) connection: A concatenation of (digital) transmission channels or (digital) telecommunication
circuits, switching and other functional units set up to provide for the transfer of (digital) signals between
two or more points in a telecommunication network to support a single communication.
TFTS connection: A connection that is established through TFTS between specified TFTS reference
points.
TFTS connection type: A description of a set of TFTS connections which have the same characteristics.
3.2 Abbreviations
For the purposes of this ETS, the following abbreviations apply:
AC Administrative Centre
AEEC Airlines Electrical Engineering Committee
AEN Aircraft Equipment Number
APC Aeronautical Public Correspondence
APGS AirPort Ground Stations
ARINC Aeronautical Radio INCorporated
AS Aircraft Station
ASI Aircraft Station Identity
AT Avionics Termination
ATE Airborne Telecommunications Equipment
ATEI Aircraft Termination Equipment Identifier
BCCH Broadcast Control Channel
C/No Carrier / Noise density
CC Call Control
CCd Country Code
CCM Call Control Management
CCITT Consultative Committee on International Telegraphy and Telephony
CEI Content of Information Element
CEPT European Conference of Postal and Telecommunications Administrations
CM Connection Management
DCCH Dedicated Control Channel
DDI Direct Dial In
DTE Data Terminal Equipment
DTMF Dual Tone Multi-Frequency
EAEC European Airlines Electronics Committee

Page 13
ETS 300 326-3: January 1996
FACCH Fast Associated Control Channel
GCC Ground switching Centre Code
GCT Ground station Cell Type
GN Ground Network
GS Ground Station
GSC Ground Switching Centre
GSIC Ground Station Identity Code
GSN Ground station Serial Number
GSS Ground Station System
HRM Handover Resource Management
IEI Information Element Identifier
ISDN Integrated Services Digital Network
IWF InterWorking Function
LI Length Indicator
MR Maintenance Resource
MRM Maintenance Resource Management
NMC Network Management Centre
OM Operations and Maintenance
OMC Operations and Maintenance Centre
OSI Open Systems Interconnection
PAD Packet Assembler Disassembler
PDU Protocol Data Unit
PSPDN Packet Switched Public Data Network
PSTN Public Switched Telephone Network
RF Relay Function
RR Radio Resource
RRM Radio Resource Management
SABM Set Asynchronous Balanced Mode
SACCH Slow Associated Control Channel
SAP Service Access Point
SDL System Description Language
SP SPare
TCH Traffic Channel
TDMA Time Division Multiple Access
TE Terminal Equipment
TFTS Terrestrial Flight Telephone System
TI Transaction Identifier
TRM Terrestrial Resource Management
UA Unnumbered Acknowledgement
WARC 92 World Administrative Radio Conference 1992
WOW Weight On Wheels
4 TFTS network architecture
4.1 General
The basic network architecture of the TFTS is described in ETS 300 326-1 [1]. The following subclauses
elaborate some of the functions performed by the entities of the TFTS.
4.2 The functional entities of the TFTS
To provide the TFTS service it is necessary to define some specific functions. These functions may be
implemented in, or gathered into, different equipments. In any case, exchanges of data occur between
these functions.
4.2.1 The Ground Station System (GSS)
The radio equipment of a GSS (transceivers, controllers, etc.) may sustain one or more cells. A GSS may
consist of one or more Ground Stations (GS). Where a GS-GSC interface is implemented, it shall consist
of one GSC and several GSs.
Page 14
ETS 300 326-3: January 1996
There are three different types of GSs as described in ETS 300 326-1 [1]:
- airport stations;
- intermediate stations; and
- en-route stations.
4.2.2 The GSC
The GSC constitutes the interface between the radio system and the fixed networks. It performs all the
switching functions for ASs located in a geographical area designated as the GSC area. The main
difference between a GSC and an exchange in a fixed network is that the GSC takes into account the
impact of the allocation of radio resources and the mobile nature of the subscribers and performs in
addition, at least the following procedures:
- procedures for call-set up;
- procedures required for the aircraft access validity check;
- procedures required for handover;
- procedures for Operations and Maintenance (OM).
4.2.3 The GS
A GS is a network component which comprises the transceiver equipment needed to establish the radio
link between the GN and ASs. The GS services one cell and is controlled by a GSC.
4.2.4 The Interworking Function (IWF)
The IWF is an entity associated with the GSC. The IWF provides the functionality necessary to allow
interworking between the TFTS network and the fixed networks (i.e. Public Switched Telephone Network
(PSTN), Integrated Services Digital Network (ISDN) and Packet Switched Public Data Network (PSPDN)).
The IWF converts the protocols used in the TFTS network to those used in the appropriate fixed network.
The IWF may have no functionality where the service implementation in the TFTS network is directly
compatible with that at the fixed network. The interworking requirements are described in clause 5.
4.2.5 The AS
A description of an AS is given in ETS 300 326-1 [1], subclause 4.3.1.
4.3 Configuration of the TFTS network
4.3.1 General
The basic configuration of the TFTS network and the interconnection to the PSTN, ISDN and PSPDN is
presented in figure 1. This configuration presents all possible signalling interfaces which can be found in
the TFTS network. The specific implementation in each country may differ; particular functions may be
gathered in the same equipment and then these interfaces may become internal interfaces.
In any case the implementation of particular TFTS network components has no impact on the TFTS
network.
Page 15
ETS 300 326-3: January 1996
In the basic configuration presented in figure 1, all the functions are considered implemented in different
equipments. Therefore, all the interfaces within the TFTS network are external. From this configuration, all
the possible TFTS network organisations may be deduced. In the case when some functions are
contained in the same equipment, the relevant interfaces become internal to that equipment.
Figure 1: TFTS Interfaces
4.3.2 Description of the TFTS configuration
There may be none, one or more GSC interfaces from the TFTS network to the PSTN, ISDN and PSPDN
in any country. Among switching functions, the GSC performs the control of the user access to the TFTS
network. Handover functions may be performed between GSCs via the fixed networks or a dedicated
handover network. Handover functions between GSs of the same GSS or between radio channels of a GS
are performed within a GSS without the PSTN, ISDN or PSPDN being involved.
There is an Administrative Centre (AC) which may perform the following functions:
- data collection to support billing; and

Page 16
ETS 300 326-3: January 1996
- other service oriented central tasks.
There is a Network Management Centre (NMC) which supports management tasks that need to be
globally coordinated for the system.
The system and equipment Operations and Maintenance (OM) within one or several GSS are performed
by an Operation and Maintenance Centre (OMC).
The AC, NMC and OMC communicate to the GSSs via the fixed networks.
4.4 TFTS network interfaces
4.4.1 General
The implementation of the TFTS service implies the exchange of data between the equipments involved
in the service.
4.4.2 Interface between the GSC and GSs (Ub)
A description of a possible interface between the GSC and its GSs is the subject of an ETSI Technical
Report (ETR) in preparation.
4.4.3 Interface between AS and GS system (Ua)
The interface between the AS and the GS is described in ETS 300 326-2 [2].
4.5 Interfaces with the fixed networks
4.5.1 Interface between the GSC and the fixed networks
In order to perform the required functions of the TFTS network there are five different types of interfaces
between the GSC and the fixed network:
- the user traffic interface (1a);
- the handover interface (1b);
- the AC interface (1c1);
- the NMC interface (1c2);
- the OM interface (1c3).
The interfaces with fixed networks, including dedicated networks, are described in this part.
The GSC 1a and 1b interfaces interface to the fixed network(s) without causing any changes to the fixed
networks(s).
The GSC 1b interfaces (i.e. handover) is used to support handover between different GSSs within the
TFTS. This interface is described in clause 6.
The GSC 1c1 interface is used for communication with the Administration Centre.
The GSC 1c2 interface may be used to communicate directly with the NMC.
The GSC 1c3 interface is used to communicate with the OMC.
4.5.2 Scope of TFTS specification
With the exception of the data aspects and interface requirements defined in ETS 300 326-1 [1] and
clause 5, the specification of interfaces 1c1, 1c2 and 1c3 is outside the scope of this ETS.

Page 17
ETS 300 326-3: January 1996
4.6 Interfaces between AC, OMC and NMC, and the fixed networks
The specification of interfaces 2c1 and 2c2 is outside the scope of this ETS.
4.7 Network connection types
4.7.1 Introduction
The TFTS may be described by a limited set of access interfaces and a limited set of TFTS connection
types to support the telecommunication services described in ETS 300 326-1 [1]. This subclause identifies
and defines these connection types in so far as they relate to the particular network capabilities.
The basic lower layer capabilities shall be represented by a set of connection types. The definition of a set
of connection types shall provide the necessary information to identify network capabilities of TFTS. In
addition to describing network capabilities the identification of connection types shall facilitate the
specification of network-to-network interfaces. It may also assist in the allocation of network performance
parameters.
4.7.2 General considerations
Low layer capabilities are defined in ETS 300 326-1 [1], clause 5. All Bearer Services shall be provided
using low layer capabilities in the connection mode.
4.7.2.1 Relationship between lower layer capabilities and radio traffic channels
The realization of lower layer capabilities for the provision of telecommunication services shall make use
of a physical medium consisting of Traffic Channel (s) (TCH). For each connection at least one TCH shall
be used, and no multiplexing of low data rate connections on one TCH is allowed.
4.7.2.2 Lower layer capabilities
One class of lower layer capabilities is identified and is a transparent class which is characterized by
constant throughput, constant transit delay and variable error rate, which is applicable to speech services.
The definition described above provides the basis for the definition of a limited set of connection types to
be implemented by a TFTS.
4.7.3 Framework for the description of connection types
4.7.3.1 Introduction
TFTS shall provide a set of network capabilities which enable telecommunication services to be offered to
a user.
A TFTS connection shall be a connection established between TFTS reference points.
NOTE: A TFTS connection type is a way of referring to, and describing, a TFTS connection.
Therefore, each TFTS connection may be characterized as belonging to a particular
connection type.
Page 18
ETS 300 326-3: January 1996
Figure 2 illustrates the concepts.
Figure 2: Framework for the description of TFTS connections
4.7.3.2 Purpose of TFTS connection types
The definition of a set of TFTS connection types shall provide the necessary input to identify the network
capabilities of a TFTS. Other key requirements of TFTS are contained in ETS 300 3261 [1]. In addition to
describing network capabilities of TFTS, the identification of connection types shall facilitate the
specification of network-to-network interfaces. It may also assist in the allocation of network performance
parame
...